|
| |
|
| |
 |
|
|
|
|
|
|
|
| | Introduction
In today's MTV-world, there is a new emphasis on the visual in general and lighting in particular. Fiber optics is a key way for an organization to make its booth not only more attractive, but also stand out from others.
| What It Is
When we first began working with fiber optics in 1984, little was known about its use for anything, let alone something visual. Even after explaining its structure, folks seemed mystified. But fiber optics is actually quite a simple concept. The angle at which light bends when it passes through an object is called its refractive index. A plastic fiber optic strand is made up of two separate materials: the core and the cladding. The core has a higher refractive index (or angle at which light bends) than the cladding. This creates a barrier for the light, and it must bounce along the length of the fiber until it reaches an opening in the cladding. Plastic fiber is referred to as PMMA or polymethlmethacrylcate.
There are three major forms of fiber optics in the marketplace today. The first is end-lit fiber. This means light enters one end of the fiber (the input end) and travels the length of that fiber until it reaches the part that is viewed (the output end). This form of fiber is also called "point to point" since graphics are created using a series of dots. The second form of fiber optics is called edge-lit or linear fiber. The cladding in this fiber has been degraded, allowing light to leak all along its length. The effect is a glowing strand much like neon. And, finally, there are fiber pegs. These are pegs that are dyed different colors and backlit with fluorescent lighting.
Lighting a fiber optic strand means putting a bulb of some sort (typically a halogen lamp) at the input end. By introducing a color wheel in between the bulb and the fiber, one can change the color of light passing through the fiber. As the wheel moves past many fibers, consecutive action occurs or what we call implied motion. Changing colors in a directional fashion over various graphics causes the animation created with color wheels. Fiber elements can be turned on and off either by turning the bulbs on and off or by placing black on the color wheel.
Fibers can be obtained in various diameters. The sizes are generally referred to by stating their diameter as a fraction of an inch, such as .020" diameter. The most popular sizes range between .010" diameter (very hair fine fiber) to .120" diameter fiber (very thick rigid fiber). There are other large core diameter fibers, although these are generally used for lighting and will not be discussed in this chapter.
The size of the fiber used for a display depends on many variables such as viewing distance, indoor or outdoor applications, detail, and budget. Fiber pricing increases geometrically from one size to another. Thus, a sign using 1000 .030" diameter fibers(.030" diameter is the most widely used and cost effective size) would cost about $875. The same sign with .060" diameter fiber would cost about $1,475. A reputable fiber optic fabricator can determine what is the best fiber to use in displays.
The lamps used to light fiber optic graphics are varied. As we stated earlier, halogen is the most common. A 50-watt halogen lamp is a perfect choice. Its color temperature provides a very white light that transmits through colored ink or gels to provide excellent matches for almost any pantone shade. The average life of a 50-watt halogen lamp has been increased to around 5000 hours. This means having to change lamps only once every 6 months or so if the sign is left on 24 hours a day. The lamps are 12 volt and require very little electricity so they are extremely cost effective to use. Most small signs require only 1 amp of electricity. Larger signs-say, a fiber optic wall containing up to 10 individual illuminators-will still only require 10 amps to power.
Another element of a fiber optic illuminator includes a synchronous motor and a transformer, which converts line current (120V or 240V electricity) to the 12 volts required by most of the components.
The color wheel is probably the most creative portion of the display. Custom handmade wheels utilize theatrical gels for the color. These are now made from polyester so they will not fade or deteriorate over time. Silk-screened wheels are made using special UV retardant inks and last years and years. The color wheels themselves are made of acrylic or polycarbonate.
We have now described the fiber optics themselves and the illuminators. The rest of the story depends on the application and the graphics. We now know that the input end of the fiber is considered the end connected to the illuminator. The output end is the visible part of the display. The output end is placed into a substrate of some kind. This is done by drilling holes in materials such as plastic or wood. Fiber strands are inserted into the holes and then glued in place. The loose end (the end that will become the in put end) is then bundled so the light will pass over the fibers in a directional fashion creating the correct sequencing of a display. Since fiber occupies space and illuminators are set up to handle a certain number of fiber strands, sometimes more complicated displays require more illuminators. These may have to be synchronized. These can also be made to interact via buttons or laser discs or other form of "triggering" devices. Sound can be added and a multimedia event can be created. The sky is the limit! What you can dream can be rendered using fiber optics.
| |
|
|
|
|
|
|
|
|
